
battery() = @ccall lib.wb_robot_battery_sensor_get_value()::Cdouble
function battery_enable(sampling_period)
    @ccall lib.wb_robot_battery_sensor_enable(sampling_period::Cint)::Cvoid
end
function battery_disable()
    @ccall lib.wb_robot_battery_sensor_disable()::Cvoid
end
function battery_sampling_period()
    @ccall lib.wb_robot_battery_sampling_period()::Cint
end